The federal government will consider selling the profitable loans business of the $10 billion Clean Energy Finance Corporation.

The government is committed to abolishing the CEFC, but Finance Minister Mathias Cormann has revealed the private sector could be invited to bid for the niche lending business it has carved out since being established as part of Labor's carbon tax package.

''You can assume it's not something we would want to keep on our books forever and a day,'' Senator Cormann told a budget estimates hearing of the Senate's economics legislation committee.

Senator Cormann, who is driving the sale of Medibank Private, said ''any sale of transfer of the asset into the private sector'' would have to maximise value for the taxpayer and not destabilise any private investment market in renewable energy.

The executive director of Treasury's fiscal group, Nigel Ray, told the hearing that KPMG had been engaged to do some preliminary planning on how to transition the loans book of CEFC back into Treasury once the agency was abolished, but said no formal scoping study into a privatisation had begun.

Senator Cormann said no decisions could be made until the Senate voted to abolish the CEFC.

In December, Labor and the Greens split Abbott's package of carbon repeal bills and have voted against abolition of the CEFC.

The chief executive of the CEFC, Oliver Yates, said the agency, created in July last year, had so far lent $700 million and ''mobilised'' $2.5 billion when finance from the private sector into the same projects was included. It has $11 billion worth of projects in the pipeline.

The cost of finance for the CEFC is roughly 3.5 per cent and it lends to renewable and energy efficiency projects at about 7 per cent. In less than 12 months, the agency is already covering its own costs and is forecast to deliver yearly profits of $200 million.

Mr Yates told the hearing that if the CEFC was allowed to continue on its course to invest $5 billion, it would be responsible for one fifth of the government's target to reduce carbon emissions by 5 per cent by 2020.

While in opposition, the Coalition dubbed the CEFC a ''giant green hedge fund'' and ''Bob Brown's Bank''.

''Right across Australia people are turning waste into energy, creating energy savings from manufacturing and the buildings they own,'' Mr Yates said.